Annals of Vascular Surgery
Volume 24, Issue 2 , Pages 160-166, February 2010

Endovascular Treatment of Traumatic Thoracic Aortic Injuries: Short- and Medium-term Follow-up

Department of Angiology, Vascular and Endovascular Surgery, Hospital Universitari Vall d'Hebron, Universitat Autonoma de Barcelona, Barcelona, Spain

published online 09 November 2009.

Article Outline

Background

Successful thoracic endovascular aortic repair (TEVAR) with low rates of complications has been referred to in the treatment of traumatic thoracic aortic injuries; however, we still do not know the long-term behavior. In this series, short- and intermediate-term results of TEVAR of traumatic aortic injuries are analyzed.

Methods

The clinical charts and courses of 20 patients (mean age, 31.8 years; age range, 15-65 years; 14 [70%] men) with traumatic thoracic aortic injuries treated with TEVAR were retrospectively reviewed. Mean delay from trauma to intervention was 15 days (range, 0-180 days).

Results

The initial success rate was 100%, with no deaths or intraoperative leaks, although in 4 (20%) patients, injuries were repaired in the arterial access site. The mean postoperative follow-up was 43.53 months (range, 5.5-108.0 months). Four (20%) patients required reintervention: 2 postoperative revascularizations of the left subclavian artery (20% of the patients in whom the ostium was intentionally occluded) and 2 aortic reinterventions (endovascular treatment of a collapsed stent graft and open repair after thrombosis of another stent graft). All reinterventions were successfully performed and no additional complications were registered during follow-up. Asymptomatic findings related to the stent graft included lack of proximal device-wall apposition in 8 patients (40%), intragraft mural thrombus formation during the first 6 months in 7 patients (35%), and an asymptomatic fracture of the longitudinal reinforcing bar of the stent graft 4 years later in 1 patient (5%).

Conclusion

Although not completely exempt of complications, TEVAR provides a reliable method for the treatment of traumatic thoracic aortic injuries with good results in the short- and medium-term follow-up. All complications have been treated successfully. Long-term evolution of lack of proximal device-wall apposition and intragraft mural thrombus formation should be closely monitored to prevent long-term complications.

 

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Introduction 

Although infrequent, traumatic thoracic aortic injuries are a potentially life-threatening complication. Up to 85% of cases result in death at the site of the accident or during transfer to hospital, and an additional 5% to 10% die during the first 6 hours after arrival.1, 2, 3 Up to 90% of patients have associated injuries that may ultimately condition their prognosis.4

Successful thoracic endovascular aortic repair (TEVAR) with relatively low rates of complications have been referred in treatment of traumatic thoracic aortic injuries: compared to open surgery, TEVAR has been associated with lower perioperative mortality rate (15.2% vs. 7.6%)5 and during the first 30 days (20% vs. 8%),6 paraplegia (5.6% vs. 0%), and stroke (5.3% vs. 0.9%).5, 7 However, follow-up is usually short in these series,5, 6 as there are few series with a mean follow-up longer than 40 months.8 For this reason, we do not know the long-term behavior and possible late complications of the stent grafts under these circumstances.

The aim of this work is to retrospectively review the results, clinical course, and complications of those patients treated in our institution for traumatic thoracic aortic rupture using TEVAR, with a mean follow-up of more than 40 months.

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Patients and Methods 

A total of 20 patients were treated in our institution by endografting of acute or subacute traumatic thoracic aortic injuries in the last 9 years (from November 1999 to August 2008). All of them were admitted at the trauma unit of our hospital, directly or being transferred from other centers. A thoracic and abdominal angio–computed tomography (angio-CT) were immediately obtained after admission.

Most of the patients were men (14 [70%] men and 6 [30%] women), with a mean age of 31.8 years (age range, 15-65 years). The cause of the injury was a traffic accident in 16 (80%) patients (motorbike, 55%; car, 20%; and pedestrian hit by a vehicle, 5%), precipitations in 3 (15%), and a work-related accident in 1 (5%). The injuries were located in the aortic arch in 90% of patients (distal zone 2 or zone 3)9 and in the descending thoracic aorta (zone 4) in 10% (Fig. 1A).

  • View full-size image.
  • Fig. 1 

    Intraoperative angiogram of a traumatic injury of the thoracic aorta (A) and the postoperative follow-up angio-CT, showing a lack of device-wall apposition of the proximal segment of the endograft (B).

All patients had associated injuries, the most frequent being hemothorax or other lung or mediastinal injuries in 16 (80%) patients, pelvic fractures in 11 (55%), lower limbs fractures in 9 (45%), brain injuries in 9 (45%), intra-abdominal injuries in 9 (45%), and spine fractures in 6 (30%).

The emergency status for the repair depended on the hemodynamic stability of the patient and the presence of life-treating associated injuries. Mainly for that reason, the mean delay of the intervention after the injury was 15 days (range, 0-180 days); 10 (50%) patients underwent repair acutely (before 14 days) and the remaining 10 patients, subacutely (from 14 to 180 days). There were no complications attributable to the delay in the procedure. Chronic traumatic lesion repairs (acute nontreated lesions developed over years) were excluded, as it represents a clinical and anatomical distinct situation. All the procedures were performed in the operating room, under general anesthesia and orotracheal intubation. Fluoroscopic monitoring was used in all patients (using a Philips BV29 mobile C-arm in the initial patients, and subsequently a Philips BV Pulsera R2.2.4), and transesophageal echocardiography (TEE) was used in all patients except for one (because of nonavailability).

Briefly, the standard procedure included open dissection of an access artery to introduce the stent graft (usually the right common femoral artery, combined, in only one patient, with an iliac access due to the small caliber of the femoral artery). Percutaneous arterial access was also achieved for angiographic guidance, usually via the contralateral femoral (contralateral common femoral artery in 18 [90%] patients and brachial artery in 2 [10%]).

After systemic heparinization, a pigtail catheter was inserted, via the percutaneous arterial access, up to the ascending aorta, obtaining an angiogram of the aortic arch and descending thoracic aorta. The guide wire, via the open access, was changed for a rigid one (Lunderquist; Cook, Bloomington, IN), over which the selected stent graft was introduced up to the thoracic aorta. To ensure a correct placement of the proximal fixation, a new angiogram was obtained under magnification previously to the release of the device. Brief apnea and low blood pressure using endovenous drugs (trying to reach a systolic blood pressure of less than 110 mm Hg) were maintained during this maneuver.

The stent graft commercial devices included 9 (45%) Medtronic Talent or Valiant Thoracic Stent Graft (Medtronic AVE, Santa Rosa, CA), 6 (30%) Gore Excluder or TAG Endoprothesis (WL Gore & Associates, Flagstaff, AZ), 3 (15%) Bolton Relay Thoracic Stent-Graft (Bolton Medical, Sunrise, FL), and 2 (10%) Cook Zenith TX2 TAA Endovascular Graft (Cook). One device per patient was used, except in one patient in whom two devices were used (mean of 1.05 device implants per patient). The mean diameter of the stent grafts used was 26.05 mm (range, 20-34 mm). Thoracic stent grafts were mainly used, except in one patient for whom an iliac extension of an abdominal aortic device was required.

Anchoring proximally to the left common carotid artery ostium was not required in any patient. Proximal fixation was placed proximally to the left subclavian artery (zone Z2) when the distal thoracic aortic segment was short or excessively angled (10 [50%] patients). In these patients, an intentional occlusion of the left subclavian artery (LSA) was performed with no combined revascularization procedures. In the remaining patients, proximal fixation was placed in the aortic arch distally to the LSA (landing zone Z3) in 9 (45%) patients or in the descending thoracic aorta (landing zone Z4) in 1 patient.9 The mean aortic diameter in the proximal landing zone was 21.13 mm (range, 16-28 mm) and 19.89 mm (15-29 mm) in the distal landing zone. The mean proximal oversizing was 23.2% (range, 12% to 40%).

An angioplasty balloon was used to dilate the stent graft in those patients in whom the fluoroscopic examination or TEE revealed inadequate proximal or distal fixation or a type I leak, after releasing the device. Prophylactic treatment with low-molecular-weight heparin was given during the hospital stay, starting antiplatelet treatment on discharge (usually 100 mg acetylsalicylic acid/day). Postoperative follow-up consisted of a clinical examination, angio-CT, and simple chest radiograph, at 1, 6, and 12 months after the procedure and then annually.

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Results 

All the procedures were successfully completed, with no deaths during the operation or at 30 days. No paraplegia or neurological injuries were registered. There were neither immediate conversion to open surgery nor immediate postoperative leaks. Injuries in the arterial access site were shown in 4 patients (20%), and all of them were repaired during the same procedure. Interposition of a Dacron graft was needed in two patients, patch angioplasty in one patient, and thrombectomy of the iliac artery in another patient.

The mean postoperative follow-up was 43.53 months (range, 5.5-108.0 months). There were no deaths during this period. LSA revascularization (left carotid–LSA bypass) was performed at 35 and 37 days after surgery in two patients with occlusion of the LSA (20% of the patients in whom the ostium was intentionally occluded). Indications for these secondary procedures were steal syndrome with symptomatic vertebrobasilar artery insufficiency in one patient and arm claudication in another one. Both patients currently remain asymptomatic.

Lack of apposition of the proximal segment of the endograft to the inner curve of the aortic arch10, 11 was observed intraoperatively or on the first control angio-CT in eight patients (40%; Fig. 1B), corresponding to a bare stent of the proximal segment of the device in three of them (38%). None of these patients had an early type I endoleak, and only one of them had a late type I endoleak and collapse (described later).

A fracture of the longitudinal reinforcing bar of the stent graft was also detected 4 years after the primary procedure in a patient with an Gore Excluder Endoprothesis (WL Gore & Associates). Conservative management and close follow-up were decided for this patient, who remains asymptomatic 2 years after the diagnosis (Fig. 2A).

  • View full-size image.
  • Fig. 2 

    Findings during postoperative follow-up using angio-CT: rupture of the longitudinal reinforcing bar of the stent graft (A) and appearance of intragraft mural thrombus (B).

Intragraft mural thrombus formation (defined as an intraluminal, parietal area within the stent graft not enhanced on angio-CT)12, 13 was observed in seven patients (35%) during follow-up (Fig. 2B). In all of them, the clot was initially detected during the first 6 months after surgery. There was no evidence of significant progression of the area occupied by the clot during follow-up or any major complications in this group.

There were two major complications (10% of the series) that required aortic reintervention. The first case was a 40-year-old patient with a Gore TAG Endoprothesis (WL Gore & Associates) with an 18% oversizing. Although a lack of proximal device-wall apposition was observed, the postoperative course was uneventful. Six months after the procedure, a large proximal type I endoleak appeared and the stent graft collapsed, which required a proximal repair overlapping a TAG extension graft within the previously collapsed device and covering the LSA, and reexpansion was achieved.14 The patient is currently asymptomatic, and the device is patent with no leaks.

The second case, a 17-year-old patient treated with a Cook Zenith TX2 TAA Endovascular Graft (Cook),15 developed a nearly occlusive parietal thrombosis of the stent graft 1 year after the initial procedure. An emergency axillofemoral bypass graft was performed, allowing conversion to successful definitive repair consisting of an extra-anatomic bypass from the ascending aorta to the supraceliac abdominal aorta. The patient is currently asymptomatic. Interestingly, no intragraft mural thrombosis or proximal fixation defects were observed in this patient during early follow-up.

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Discussion 

In the present series, 20 patients with thoracic aortic injuries were treated, with a mean postoperative follow-up of 45.53 months. There were no deaths, paraplegia, or other neurologic injuries during or after the procedure. Although there were two major complications (collapse and thrombosis of the endograft, 6 months and 1 year after the initial procedure, respectively), both were successfully solved.

The timing of the intervention is essential to get satisfactory results. Although some initial studies support immediate repair in all patients,2 better results have been observed in those patients where the procedure can differ depending on the hemodynamic stability, angio-CT findings, and other associated life-threatening injuries.16, 17 In fact, these are usually polytraumatic patients, with a high incidence of associated injuries in other areas (100% of the patients in the present series), who require other priority procedures in many cases. In the present series, emergency interventions on the thoracic aorta were avoided, if possible, with a mean surgical delay of 15 days. There were no complications attributable to this delay in any of the patients. Although in some of them this delay was extended (up to 180 days), the anatomy and treatment of these injuries are still very different from those followed for patients with chronic traumatic lesions, not included in the series.

The use of TEVAR in thoracic aorta injuries appears to give better short-term results than open surgery.5, 6, 7, 18 However, due to the young age of some patients and the limited size of their femoral arteries, injuries at the access site are common, needing iliac access in up to 16% of cases in some series.19 In the present series, only one iliac access was required due to a small-diameter femoral artery. Lesions of the femoral artery developed in four patients (20%). All of them were repaired during the same procedure and no subsequent complications were related during the follow-up. A reduction in the introducers, greater flexibility of the devices, and efficient preoperative planning could probably reduce these complications.

In our experience, preoperative anticoagulation has not entailed any additional morbidity, nor did we observe bleeding in other areas, possibly due to treating stable patients. Considering the characteristics of these patients (usually young patients, arteries very susceptible to spasm, angled aortic arches, and the need to use large-caliber devices), we believe that anticoagulation can be beneficial if there is no active bleeding.

On the other hand, the particular anatomy of these patients may lead to additional complications. They usually have small aortic diameters and acute angled arches, with lesions very near the LSA.20 These circumstances (excessive oversizing with the currently available devices, and deficiencies in the proximal fixation due to significant angulations, as well as avoidance of intentionally covering the LSA) may lead to a type I proximal leak and collapse of the device. These serious complication14, 21, 22 may benefit from an endovascular treatment, as described in the present series.

Although intentional occlusion of the LSA (50% of the patients in this series) might improve proximal fixation of the device, it is not exempt from complications. Besides clinical ischemia of the upper limb and LSA steal (the reason for subsequent revascularization in 2 [20%] of the patients in whom its ostium was intentionally occluded), some groups have referred an increase of stroke9 or paraplegia23 under this situation. Lower rates of neurologic complications have been published after selective revascularization of the LSA.24 However, most of these series are heterogeneous mixtures of patients with different pathologies of the thoracic aorta, and extrapolation of these results to patients with traumatic injuries is still controversial. Our current attitude is to perform a preliminary selective revascularization of the LSA when this has to be occluded (dominant left vertebral artery, lesions on the right vertebral, subclavian or brachiocephalic trunk arteries, supra-aortic or basilar artery abnormalities, or because of a previous left internal mammary coronary bypass or hemodialysis fistula in the left arm).

The use of perioperative TEE is helpful for visualizing the extent of the lesion and for tracking the placement and release of the stent graft at the proximal landing zone. In addition, TEE may help to verify the complete covering of the lesion and presence of leaks and to assess potential lesions at the supra-aortic trunks.25 More recently, the use of intravascular ultrasound (IVUS) has been described with similar goals.26

Oversizing of the grafts was 23.2% in the present series, mainly due to the lack of commercial devices with adequate diameters to the small treated aortas. Although oversizing was greater than the 20% advised by various groups,27 the main complication associated with the excessive oversizing (collapse) occurred in one of our patients with an adequate oversizing (18%). Therefore, our current attitude is to avoid excessive oversizing (<20%) whenever possible.

Lack of apposition of the proximal segment of the endograft to the inner curve of the aortic arch was a common finding during follow-up (eight [40%] patients). In three (38%) patients, this defect affected only the proximal bare stent of the graft. Although it could be associated with the subsequent appearance of complications (type I leaks and collapse of the device), none of these patients had an early type I endoleak, and only one of them had a late endoleak and collapse (one of eight patients [12.5%]). For this reason, we still do not know its clinical implication in the long term. A high-grade angulation of the aortic arch in young patients, as well as the use of inappropriate devices, may jeopardize the correct angulation and proximal fixation of the stent graft.11 Avoidance of landing of the proximal fixation of the device in the more angled areas may prevent these drawbacks. However, device collapse has also been associated with other factors,10, 21 and we do not know if this was the main cause. Therefore, in the absence of leaks or other complications, our approach in view of this lack of apposition is conservative and closed follow-up.

Intragraft mural thrombus formation was usually observed in this series. This is possibly due to changes in the postoperative flow within the stent graft in excessively oversized devices. A progressive increase of the area occupied by the clot was not observed during follow-up. It did not appear previously in the case of complete occlusion of the device nor was it associated with other complications. In view of this finding, our attitude is to maintain antiplatelet treatment in all patients, starting anticoagulation only in those cases of extensive intragraft mural thrombus or in view of its progression. Longer-term follow-up will provide more data on both findings.

Despite the good results published in several series,5, 6, 7, 8 potentially severe complications must not be underestimated after TEVAR in these patients. In the present series, there were two major complications, although they could be successfully solved. Close follow-up of these patients is essential in both immediate- and long-term postoperative periods. The results of the present series suggest that, although not free of minor or major complications, encouraging results in the short and medium term are expected. Longer follow-up will provide more information on the long-term results of these procedures.

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Conclusions 

Although not exempt of complications, TEVAR is a reliable method to manage traumatic thoracic aortic injuries, providing good results in the short- and medium-term follow-up. We do not know the long-term effects of lack of proximal device-wall apposition and intragraft mural thrombus. The strict and continued follow-up of these patients, and the knowledge of possible complications, can improve long-term patency and success rates.

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References 

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PII: S0890-5096(09)00182-4

doi:10.1016/j.avsg.2009.05.013

Annals of Vascular Surgery
Volume 24, Issue 2 , Pages 160-166, February 2010

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